KR102783429B1 - Display device - Google Patents

Abstract

A display device according to one embodiment of the present disclosure includes a first substrate, an insulating layer positioned on the first substrate and having an inclined portion, a first electrode positioned on the insulating layer, a light-emitting layer positioned on the first electrode, a second electrode positioned on the light-emitting layer, and a plurality of color conversion layers positioned on the second electrode, wherein the first electrode includes a portion inclined along the inclined portion of the insulating layer with respect to a plane parallel to the first substrate, and the light-emitting layer includes semiconductor nanoparticles.

Description

DISPLAY DEVICE

The present disclosure relates to a display device.

The display device includes light-emitting elements comprising a hole injection electrode, a light-emitting layer, and an electron injection electrode. Each light-emitting element emits light by energy generated when excitons generated by the combination of electrons and holes within the light-emitting layer drop from an excited state to a ground state, and the display device displays a predetermined image by utilizing this light emission.

The display device generally has a structure in which an anode and a cathode are arranged so as to face each other on an insulating layer covering a thin film transistor provided on a substrate, and a light-emitting layer is positioned between the anode and the cathode. However, since the light generated from the light-emitting layer is partially or completely reflected between the light-emitting layer and the electrodes, the efficiency of the light transmitted to the outside decreases.

Additionally, color shift may occur, where colors change depending on the viewing angle.

The problem to be solved by the present invention is to provide a display device capable of improving color reproducibility and reducing color shift according to viewing angle.

However, the problem to be solved by the present invention is not limited to the problem described above and can be expanded in various ways within the scope of the technical idea included in the present invention.

A display device according to one embodiment of the present disclosure includes a first substrate, an insulating layer positioned on the first substrate and having an inclined portion, a first electrode positioned on the insulating layer, a light-emitting layer positioned on the first electrode, a second electrode positioned on the light-emitting layer, and a plurality of color conversion layers positioned on the second electrode, wherein the first electrode includes a portion inclined along the inclined portion of the insulating layer with respect to a plane parallel to the first substrate, and the light-emitting layer includes semiconductor nanoparticles.

The display device further includes a pixel defining film positioned on the insulating layer, and the pixel defining film can overlap a side surface of the inclined portion.

The display device further includes a planarization layer positioned between the first substrate and the insulating layer, and an inclined portion of the first electrode positioned on an inclined portion of the insulating layer may be extended so that the second electrode may be positioned on the planarization layer.

The above pixel defining film may include dispersed nano-structured scattering particles.

The above slope can have an angle of inclination greater than 0 and less than 90 degrees.

The first electrode may include a reflective electrode.

The first electrode may include a plurality of protrusions.

The above-mentioned light-emitting layer may include quantum dots that emit blue light.

The plurality of color conversion layers include a first color conversion layer and a second color conversion layer, and the display device further includes a transparent layer adjacent to at least one of the first color conversion layer and the second color conversion layer in a direction parallel to the upper surface of the first substrate, and the transparent layer may include a plurality of scattering bodies.

The display device may further include a capping layer positioned between the second electrode and the color conversion layer.

The display device further includes a pixel defining film positioned over the insulating layer and having an opening, and the plurality of color conversion layers can be positioned within the opening.

The above-mentioned light-emitting layer can form a tandem structure including quantum dots that emit blue light.

The first substrate includes a first light-emitting region, a second light-emitting region, and a non-light-emitting region positioned between the first light-emitting region and the second light-emitting region, and the light-emitting layer can be connected across the first light-emitting region, the non-light-emitting region, and the second light-emitting region.

A display device according to one embodiment of the present disclosure includes a first substrate, an insulating layer positioned over the first substrate, a light-emitting element positioned over the insulating layer and including a light-emitting layer, a plurality of color conversion layers positioned over the light-emitting element, and a reflective metal layer positioned over the plurality of color conversion layers, wherein the light-emitting layer includes semiconductor nanoparticles.

The above reflective metal layer may include a sloped portion.

The inclined portion of the above reflective metal layer may be positioned within an opening formed between the first color conversion layer and the second color conversion layer, which are adjacent to each other among the plurality of color conversion layers.

The display device further includes a blue blocking filter overlapping the first color conversion layer and the second color conversion layer, and the blue blocking filter can be positioned between the first substrate and the insulating layer.

A display device according to one embodiment of the present disclosure includes a first substrate, a plurality of color conversion layers positioned on the first substrate, an insulating layer positioned on the plurality of color conversion layers, and a light-emitting element positioned on the insulating layer and including a light-emitting layer and a reflective electrode, wherein the light-emitting layer includes semiconductor nanoparticles.

The light-emitting element includes a first electrode positioned on the insulating layer, the light-emitting layer positioned on the first electrode, and a second electrode positioned on the light-emitting layer, and the reflective electrode may be the second electrode.

The plurality of color conversion layers include a first color conversion layer and a second color conversion layer, and the display device further includes a transparent layer adjacent to at least one of the first color conversion layer and the second color conversion layer in a direction parallel to the upper surface of the first substrate, and the transparent layer may include a plurality of scattering bodies.

According to one embodiment of the present disclosure, a display device with improved color reproducibility and reduced color shift can be implemented.

FIG. 1 is a cross-sectional view showing a display device according to one embodiment of the present disclosure.
Fig. 2 is a cross-sectional view showing a green pixel area in the embodiment of Fig. 1.
Fig. 3 is a cross-sectional view showing a blue pixel area in the embodiment of Fig. 1.
Fig. 4 is a cross-sectional view showing a light emitting element of the display device of Fig. 1.
Fig. 5 is a cross-sectional view showing a tandem structure that is a modified version of the light-emitting element of Fig. 4.
Fig. 6 is a cross-sectional view schematically showing the path of light generated in the light-emitting layer of the display device of Fig. 1.
FIG. 7 is a cross-sectional view showing an electrode including a rough structure in the embodiment of FIG. 1.
Fig. 8 is a cross-sectional view showing an example in which the light-emitting layer structure is modified from the example in Fig. 1.
FIG. 9 is a cross-sectional view showing a display device according to one embodiment of the present disclosure.
FIG. 10 is a cross-sectional view showing a display device according to one embodiment of the present disclosure.
Fig. 11 is a cross-sectional view schematically showing the path of light generated in the light-emitting layer of the display device of Fig. 10.
FIG. 12 is a cross-sectional view showing a display device according to one embodiment of the present disclosure.
Fig. 13 is a cross-sectional view schematically showing the path of light generated in the light-emitting layer of the display device of Fig. 12.
FIG. 14 is a cross-sectional view showing a display device according to one embodiment of the present disclosure.
FIG. 15 is a cross-sectional view showing a reflective metal layer including a rough structure in the embodiment of FIG. 14.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

In addition, the size and thickness of each component shown in the drawing are arbitrarily shown for the convenience of explanation, so the present invention is not necessarily limited to what is shown. In order to clearly express various layers and regions in the drawing, the thickness is shown by enlarging it. And in the drawing, for the convenience of explanation, the thickness of some layers and regions is shown exaggeratedly.

Also, when we say that a part such as a layer, film, region, or plate is "over" or "on" another part, this includes not only cases where it is "directly over" the other part, but also cases where there is another part in between. Conversely, when we say that a part is "directly over" another part, it means that there is no other part in between. Also, when we say that a part is "over" or "on" a reference part, it means that it is located above or below the reference part, and does not necessarily mean that it is located "over" or "on" the opposite direction of gravity.

Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

Additionally, throughout the specification, when we say "in plan", we mean when the target portion is viewed from above, and when we say "in cross section", we mean when the target portion is viewed from the side in a cross-section cut vertically.

FIG. 1 is a cross-sectional view showing a display device according to one embodiment of the present invention. FIG. 2 is a cross-sectional view showing a green pixel area in the embodiment of FIG. 1. FIG. 3 is a cross-sectional view showing a blue pixel area in the embodiment of FIG. 1. FIG. 4 is a cross-sectional view showing a light-emitting element of the display device of FIG. 1.

Referring to Fig. 1, a buffer layer (55) is positioned on a first substrate (50). The first substrate (50) may be transparent.

The buffer layer (55) can perform a function of preventing metal atoms, impurities, etc. from diffusing from the first substrate (50). For example, the buffer layer (55) can include silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide, silicon carbon nitride, etc. The buffer layer (55) can be omitted.

A semiconductor layer is positioned on the buffer layer (55). The semiconductor layer may include a plurality of extrinsic regions containing n-type or p-type conductive impurities and at least one intrinsic region containing almost no conductive impurities.

In the semiconductor layer, the impurity region includes source and drain regions (75, 80), which are doped with p-type impurities and separated from each other. The region between the source region (75) and the drain region (80) becomes a channel region (85). Alternatively, the impurity region (75, 80) of the semiconductor layer may be doped with n-type impurities.

A gate insulating film (65) made of silicon oxide or silicon nitride is positioned on the semiconductor layer and buffer layer (55).

A gate electrode (70) is positioned on the gate insulating film (65). The gate electrode (70) is positioned on the portion of the gate insulating film (65) where the semiconductor layer is positioned underneath.

Although not shown, a gate line connected to the gate electrode (70) is located on the gate insulating film (65).

An interlayer insulating film (90) covering a gate electrode (70) may be positioned on the gate insulating film (65). The interlayer insulating film (90) may be formed with a uniform thickness on the gate insulating film (65) along the profile of the gate electrode (70). Accordingly, a step portion adjacent to the gate electrode (70) may be created in the interlayer insulating film (90). The interlayer insulating film (90) may be formed using a silicon compound including silicon oxide, silicon nitride, silicon oxynitride, or the like. The interlayer insulating film (90) may serve to insulate the gate electrode (70) from the source electrode (95) and the drain electrode (100) described below.

A source electrode (95) and a drain electrode (100) are positioned on an interlayer insulating film (90). The source electrode and the drain electrode (95, 100) are spaced apart from each other by a predetermined interval with respect to the gate electrode (70) and are positioned adjacent to the gate electrode (70). For example, the source and drain electrodes (95, 100) may extend from the interlayer insulating film (90) positioned above the source and drain regions (75, 80), respectively, to the interlayer insulating film (90) positioned above the gate electrode (70). In addition, the source and drain electrodes (95, 100) penetrate the interlayer insulating film (90) and contact the source and drain regions (75, 80), respectively.

The source and drain electrodes (95, 100) may each include a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, etc.

Although not shown, the data line is positioned to be connected to the source electrode (95) so as to intersect the gate line on the interlayer insulating film (90).

A planarization layer (105) is positioned on the source electrode (95) and the drain electrode (100). The planarization layer (105) may have a sufficient thickness to completely cover the source electrode (95) and the drain electrode (100). The planarization layer (105) may include an organic material, a water-based material, or the like.

An insulating layer (110) having a sloped portion (120) is positioned on the flattening layer (105). A contact hole is formed in the insulating layer (110) that penetrates together with the flattening layer (105) and partially exposes the drain electrode (100). Through this contact hole, the drain electrode (100) and the first electrode (125) described below can be electrically connected.

The insulating layer (110) according to the present embodiment has a partially sunken portion. The partially sunken portion may expose a portion of the upper surface of the flattening layer (105), as illustrated in FIG. 2. A side connecting the partially sunken portion of the insulating layer (110) and the other non-sunken portion of the insulating layer (110) may form an inclined portion (120). In the present embodiment, the inclined portion (120) has a first inclined angle (θ ₁ ), and the first inclined angle (θ 1 ) may be greater than 0 degrees and less than 90 degrees. Although the first inclined angles (θ ₁ ) of each of _the three light-emitting areas (DA) illustrated in FIG. 1 are all illustrated as being the same, the inclined angles may be designed differently for each light-emitting area for the purpose of improving color change according to the viewing angle.

A first electrode (125) is positioned on the insulating layer (110). The first electrode (125) fills the aforementioned contact hole and is connected to the drain electrode (100). In the present embodiment, the first electrode (125) covers a partially sunken portion of the insulating layer (110) and includes an inclined portion positioned along the inclined portion (120). The inclined portion of the first electrode (125) may be inclined with respect to a plane substantially parallel to the first substrate (50). At this time, the inclined portion of the first electrode (125) may cover most of the inclined portion (120) of the insulating layer (110). In addition, as illustrated in FIG. 2, the first electrode (125) may contact the upper surface of the planarization layer (105) in the partially sunken portion of the insulating layer (110).

A display device including an insulating layer (110) having an inclined portion (120) as in the present embodiment may have a front-emitting method in which light is ultimately emitted in a direction from the first substrate (50) toward the insulating layer (110). In this case, the first electrode (125) may be a reflective electrode.

In the present disclosure, a reflective electrode may be defined as an electrode including a material having a property of reflecting light in order to send light generated from a light-emitting layer (135) to a second electrode (145). Here, the reflective property may mean a reflectivity for incident light of about 70% or more and about 100% or less, or about 80% or more and about 100% or less.

The first electrode (125) may include silver (Ag), aluminum (Al), chromium (Cr), molybdenum (Mo), tungsten (W), titanium (Ti), gold (Au), palladium (Pd), or an alloy thereof, and may have a triple film structure of silver (Ag)/indium tin oxide (ITO)/silver (Ag), or a triple film structure of indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO).

The first electrode (125) can be formed using a sputtering method, a vapor phase deposition method, an ion beam deposition method, or an electron beam deposition method.

A pixel defining film (130) is positioned on the insulating layer (110) and the first electrode (125). The pixel defining film (130) may be formed using an organic material, an inorganic material, etc. For example, the pixel defining film (130) may include an organic material such as a photoresist, a polyacrylic resin, a polyimide resin, an acrylic resin, etc., or an inorganic material such as a silicon compound. The pixel defining film (130) may also be formed using a photosensitive agent including a black pigment, and in this case, the pixel defining film (130) may function as a light-blocking member.

The pixel definition film (130) may have nano-structured scattering particles dispersed therein. The scattering particles may include inorganic particles or polymer particles. For example, the scattering particles may include inorganic particles such as silica, TiO ₂ , ZrO ₂ , or polymer particles such as polystyrene, polymethyl methacrylate (PMMA).

An opening (132) that exposes a part of the first electrode (125) is formed in the pixel defining film (130). The side surface of the pixel defining film (130) formed by the opening (132) may have a sloped structure, and the slope angle of this sloped structure may be substantially the same as or similar to the first slope angle (θ ₁ ) of the insulating layer (110). The substantially same or similar range may be approximately a difference greater than 0 and less than or equal to 5 degrees. Unlike this embodiment, the slope angle of the slope structure of the pixel defining film (130) may be formed differently from the first slope angle (θ ₁ ) regardless of the first slope angle (θ ₁ ) of the insulating layer (110).

The pixel defining film (130) can define an emission area (DA) and a non-emission area (PA) of the display device. The area where the opening (132) of the pixel defining film (130) is positioned corresponds to the emission area (DA), and the area where the pixel defining film (130) is positioned other than the opening (132) corresponds to the non-emission area (PA). The emission area (DA) can correspond to a portion where light is emitted from the emission layer (135) described below, and the non-emission area (PA) can correspond to the remaining area excluding the emission area (DA).

Most of the inclined portion (120) of the insulating layer (110) is located in the light-emitting area (DA), and the first electrode (125) in the light-emitting area (DA) is positioned to cover the side surface of the inclined portion (120). At this time, in the light-emitting area (DA), the pixel defining film (130) covers the portion of the first electrode (125) that covers the side surface of the inclined portion (120).

A light-emitting layer (135) is positioned on a first electrode (125) located in a light-emitting area (DA), and a second electrode (145) is positioned on the light-emitting layer (135). The first electrode (125), the light-emitting layer (135), and the second electrode (145) can form a light-emitting element.

In the embodiment illustrated in FIG. 1, the light-emitting layer (135) may extend along the side surface of the inclined structure of the pixel defining film (130) and may also be positioned on a portion of the upper surface of the pixel defining film (130). However, in a modified embodiment, the light-emitting layer (135) may be positioned only on a portion of the first electrode (125) substantially exposed by the opening (132) or on a portion of the first electrode (125) exposed by the opening (132) and extended therefrom on the inclined side surface of the pixel defining film (130).

Although not shown in FIG. 1, a hole injection layer, a hole transport layer, and the like may be included between the first electrode (125) and the light-emitting layer (135), and an electron transport layer, an electron injection layer, and the like may be included between the second electrode (145) and the light-emitting layer (135). The light-emitting layer (135) according to the present embodiment includes semiconductor nanoparticles. The semiconductor nanoparticles according to the present embodiment may include quantum dots that emit blue light. Hereinafter, a light-emitting element including a light-emitting layer (135) including semiconductor nanoparticles will be described with reference to FIG. 4.

Referring to FIG. 4, a light-emitting element according to the present embodiment includes a hole transport region (1351) on a first electrode (125), a light-emitting layer (135) positioned on the hole transport region (1351), an electron transport region (1355) positioned on the light-emitting layer (135), and a second electrode (145) positioned on the electron transport region (1355).

The hole transport region (1351) may include a sublayer positioned between the first electrode (125) and the light-emitting layer (135). The hole transport region (1351) may include at least one of a hole transport layer and a hole injection layer. The hole transport layer may perform a function of smoothly transporting holes transferred from the first electrode (125). The hole transport layer may include an organic material. For example, the hole transport layer may include, but is not limited to, NPD (N,N-dinaphthyl-N,N'-diphenyl benzidine), TPD (N,N'-bis-(3-methylphenyl)-N,N'-bis-(phenyl)-benzidine), s-TAD, MTDATA (4,4',4"-Tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine).

The light-emitting layer (135) includes a plurality of quantum dots, and the material forming the light-emitting layer (135) is not particularly limited. In addition, the quantum dots included in the light-emitting layer (135) according to the embodiment of the present invention may have a core/shell structure in which one semiconductor material surrounds another semiconductor material. The interface between the core and the shell may have a concentration gradient in which the concentration of elements present in the shell decreases toward the center.

Each of the core and the shell may include at least two kinds of Mg, Zn, Te, Se and S, and in particular, the content of Mg included in the shell may be greater than the content of Mg included in the core.

Specifically, the larger the content of Mg, the larger the band gap energy of the semiconductor. When the content of Mg contained in the shell is larger than the content of Mg contained in the core, the band gap energy of the shell can be provided in a form that surrounds the band gap energy of the core, thereby enabling more stable hole/electron injection.

In other words, when the shell contains a higher content of Mg than the core, the shell can have a HOMO energy level lower than the HOMO energy level of the core and a LUMO energy level higher than the LUMO energy level of the core. According to this core/shell energy level relationship, efficient hole and electron injection is possible, thereby increasing the luminescence efficiency of the light-emitting device.

The core may include at least one of Zn _1-x Mg _x Se, Zn _1-x Mg _x S, and Zn _1-x Mg _x Te, where x is a value greater than or equal to 0 and less than or equal to 1, and the shell may include at least one of Zn _1-y Mg _y Te, Zn _1-y Mg _y Se, and Zn _1-y Mg _y S, where y is a value greater than or equal to 0 and less than or equal to 1. At this time, the core may not include Mg so that the content of Mg included in the shell is greater than the content of Mg included in the core. For example, the core may be made of a ZnTe material and the shell may be MgTe.

Additionally, when the core includes at least one of Zn _1-x Mg _x Se, Zn _1-x Mg _x S, and Zn _1-x Mg _x Te, and the shell includes at least one of Zn 1 _- y Mg _y Te, Zn _1-y Mg _y Se, and Zn _1-y Mg _y S, the shell and the core have similar crystal structures and have similar lattice constant values representing this. Similar lattice constant values indicate excellent coherence between the core/shell.

Specifically, in the case of having a zinc blende structure, the crystal constant of ZnTe is 6.103, the crystal constant of MgTe is 6.280, and CdTe has a crystal constant value of 6.478. At this time, the difference value of the crystal constants of ZnTe (core) and MgTe (shell) according to an embodiment of the present invention may have a value smaller than the difference value of the crystal constants of ZnTe (core) and CdTe (shell), which indicates that the quantum dot according to the present invention may have superior crystal consistency compared to the existing one.

Among the core/shell quantum dots, the average particle diameter of the core may be from about 2 nm to about 5 nm. Meanwhile, the average thickness of the shell may be from about 3 nm to about 5 nm. Additionally, the average particle diameter of the quantum dots may be from about 2 nm to about 10 nm.

By variously selecting the core particle size, the average thickness of the shell, and the average particle size of the quantum dots within the ranges described above, the emission color of the quantum dots and/or the semiconductor properties of the quantum dots can be variously changed.

In this embodiment, the light-emitting layer (135) can emit blue light.

An electron transport region (1355) may be positioned on the light-emitting layer (135). The electron transport region (1355) may include a sublayer positioned between the light-emitting layer (135) and the second electrode (145). The electron transport region (1355) may include at least one of an electron transport layer and an electron injection layer. At this time, the electron transport layer may include an organic material. For example, the electron transport layer may be formed of one or more selected from the group consisting of Alq3 (tris(8-hydroxyquinolino)aluminum), PBD (2-[4-biphenyl-5-[4-tert-butylphenyl]]-1,3,4-oxadiazole), TAZ (1,2,4-triazole), spiro-PBD (spiro-2-[4-biphenyl-5-[4-tert-butylphenyl]]-1,3,4-oxadiazole), and BAlq (8-hydroxyquinoline beryllium salt), but is not limited thereto.

Fig. 5 is a cross-sectional view showing a tandem structure that is a modified version of the light-emitting element of Fig. 4.

Referring to FIG. 5, a light-emitting element according to an embodiment of the present disclosure may have a tandem structure. For example, the light-emitting layer (135) may include two layers (1352, 1353) that emit the same color or emit different colors. Both of the two layers (1352, 1353) that emit the same color may be blue light-emitting layers. One of the two layers (1352, 1353) that emit different colors may be a blue light-emitting layer, and the other may be a green light-emitting layer or a yellow light-emitting layer. Light generated from each of the two light-emitting layers may be mixed to exhibit blue or white. Without being limited thereto, the light-emitting layer (135) may include three layers that emit different colors, or three layers in which two layers are the same but one layer emits a different color. At this time, the three layers can emit red, green, and blue, or blue, yellow, and blue, respectively, and the light generated from each of the three layers can be mixed to produce blue or white.

Although not shown, a charge generation layer may be located between the two layers (1352, 1353). The charge generation layer is typically formed between adjacent light-emitting layers and serves to control the charge balance between adjacent light-emitting layers.

Referring again to Figure 1, a second electrode (145) is positioned on the light-emitting layer (135) and the pixel defining film (130). The second electrode (145) may be a semi-transparent electrode.

In the present disclosure, a semi-transparent electrode may be defined as an electrode including a material having a semi-transparent property that transmits a portion of light incident on the second electrode (145) and reflects the remaining light to the first electrode (125). Here, the semi-transparent property may mean a reflectivity for incident light of about 0.1% or more and less than about 70% or about 30% or more and less than about 50%.

The second electrode (145) may include silver (Ag), magnesium (Mg), aluminum (Al), chromium (Cr), molybdenum (Mo), tungsten (W), titanium (Ti), gold (Au), palladium (Pd), ytterbium (Yb), or an alloy thereof. In the above, the second electrode (145) was described as a semi-transparent electrode to explain the resonant structure as an example, but according to another embodiment of the present disclosure, a non-resonant structure may also be applied, and in this case, the second electrode (145) may be a transparent conductive electrode such as ITO or IZO.

As illustrated in Fig. 1, the second electrode (145) may extend from the light-emitting area (DA) to the non-light-emitting area (PA). However, the second electrode (145) may not be limited thereto and may be positioned only on the upper surface of the light-emitting area (DA) or the light-emitting layer (135).

A capping layer (150) is positioned on the second electrode (145). The capping layer (150) can extend from the light-emitting area (DA) to the non-light-emitting area (PA). The capping layer (150) can be formed using an organic material, an inorganic material, or the like. For example, the capping layer (150) can include a photoresist, an acrylic polymer, a polyimide polymer, a polyamide polymer, a siloxane polymer, a polymer including a photosensitive acrylic carboxyl group, a novolak resin, an alkali-soluble resin, silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide, silicon carbonitride, aluminum, magnesium, zinc, hafnium, zirconium, titanium, tantalum, aluminum oxide, titanium oxide, tantalum oxide, magnesium oxide, zinc oxide, hafnium oxide, zirconium oxide, titanium oxide, or the like. These can be used alone or in combination with each other.

A first color conversion layer (340R), a second color conversion layer (340G), and a transparent layer (340B) are positioned on the capping layer (150). A light-blocking member (372) is positioned between the adjacent first color conversion layers (340R) and the second color conversion layer (340G), between the first color conversion layer (340R) and the transparent layer (340B), and between the second color conversion layer (340G) and the transparent layer (340B). The light-blocking member (372) can more effectively prevent color mixing that occurs between adjacent color conversion layers (340R, 340G) and between adjacent color conversion layers (340R, 340G) and the transparent layer (340B).

Hereinafter, with reference to FIG. 2, a green pixel area including a second color conversion layer (340G) and a red pixel area having a configuration generally similar to the green pixel area will be described.

Referring to FIGS. 1 and 2, a light filter layer (350) may be positioned between the capping layer (150) and the second color conversion layer (340G). The light filter layer (350) may be positioned between adjacent color conversion layers (340R, 340G) and between adjacent color conversion layers (340R, 340G) and the transparent layer (340B). In this case, the light filter layer (350) may be positioned between the second substrate (310) and the light blocking member (372) described below based on a direction substantially perpendicular to the first substrate (50). The light filter layer (350) serves to reflect light generated from the first and second color conversion layers (340R, 340G) to increase light efficiency. Specifically, the light filter layer (350) causes the blue light generated from the light-emitting layer (135) to meet the semiconductor nanoparticles of the color conversion layer (340R, 340G) and is scattered in a Lambertian manner into red or green, and recycles the red or green light that is emitted to the side and bottom instead of the front, and causes it to be emitted to the front.

The optical filter layer (350) includes a plurality of layers, and the plurality of layers may have a structure in which at least two layers having different refractive indices are alternately arranged in a direction substantially perpendicular to the first substrate (50).

An auxiliary metal layer (362) is positioned between the second color conversion layer (340G) and the light-shielding member (372). The auxiliary metal layer (362) may be a metal material capable of reflecting light, and may reflect light incident on the auxiliary metal layer (362) back to the color conversion layer (340R, 340G), the transmission layer (340B), or the second substrate (310) to increase the amount of light emitted to the user. The auxiliary metal layer (362) may be omitted.

A blue blocking filter (322) is positioned on the second color conversion layer (340G). The blue blocking filter (322) is also positioned on the first color conversion layer (340R). The blue blocking filter (322) has the following role. When a light-emitting layer (135) including a blue light-emitting material is used, it prevents color mixing from occurring in the process of blue light passing through the first color conversion layer (340R) and the second color conversion layer (340G) to implement red and green, respectively. Specifically, the blue blocking filter (322) blocks blue light that is not absorbed by the first color conversion layer (340R) and the second color conversion layer (340G) from escaping to the outside, so that the blue blocking filter (322) overlapping the first color conversion layer (340R) can transmit pure red light that is not mixed with blue light, and the blue blocking filter (322) overlapping the second color conversion layer (340G) can transmit pure green light that is not mixed with blue light.

In FIGS. 1 and 2, the blue blocking filter (322) is positioned in an area corresponding to the first color conversion layer (340R) and the second color conversion layer (340G), and the blue blocking filters (322) positioned in each area are shown as being separated from each other. However, unlike this, the blue blocking filter (322) formed on the first color conversion layer (340R) and the blue blocking filter (322) formed on the second color conversion layer (340G) may be connected to each other.

In this embodiment, the first and second color conversion layers (340R, 340G) and the transparent layer (340B) may include a photosensitive resin. The quantum dots included in the first and second color conversion layers (340R, 340G) may be selected from a II-VI group compound, a III-V group compound, an IV-VI group compound, a IV group element, a IV group compound, and a combination thereof.

The group II-VI compound is a binary compound selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS and mixtures thereof; a ternary compound selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS and mixtures thereof; And the group consisting of quaternary compounds selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof. The group III-V compound may be selected from the group consisting of binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb and mixtures thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb and mixtures thereof. And a group consisting of four-element compounds selected from the group consisting of GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, GaAlNP, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb and mixtures thereof. The Group IV-VI compound may be selected from the group consisting of a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe and mixtures thereof; a ternary compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and mixtures thereof; and a group consisting of four-element compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe and mixtures thereof. The Group IV element may be selected from the group consisting of Si, Ge and mixtures thereof. The group IV compound may be a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

At this time, the binary, ternary or quaternary compound may exist in the particle at a uniform concentration, or may exist in the same particle with a partially different concentration distribution. In addition, one quantum dot may have a core/shell structure surrounding another quantum dot. The interface between the core and the shell may have a concentration gradient in which the concentration of the element existing in the shell decreases toward the center.

Quantum dots can have a full width of half maximum (FWHM) of an emission wavelength spectrum of about 45 nm or less, preferably about 40 nm or less, and more preferably about 30 nm or less, and color purity or color reproducibility can be improved within this range. In addition, since light emitted through these quantum dots is emitted in all directions, the viewing angle can be widened.

In addition, the shape of the quantum dot is not particularly limited to a shape commonly used in the field, but more specifically, a shape such as a spherical, pyramidal, multi-arm, or cubic nanoparticle, nanotube, nanowire, nanofiber, or nanoplatelet particle can be used.

Below, the blue pixel area including the transparent layer (340B) will be described with reference to FIG. 3.

The transmission layer (340B) is made of a transparent polymer, and the blue light supplied from the light-emitting layer (135) is transmitted through it and exhibits a blue color. The transmission layer (340B) corresponding to the area that emits blue light includes a material that emits incident blue light without a separate fluorescent substance or quantum dot. For example, the transmission layer (340B) may be a polymer such as a photosensitive resin.

In the present embodiment, the transmitting layer (340B) may further include a scatterer (335). The scatterer (335) may make the front brightness and the side brightness of the light emitted from the transmitting layer (340B) uniform. The scatterer (335) may be any material that can evenly scatter the light, and as an example, may be any one of silica (SiO ₂ ), hollow silica (SiO ₂ having a hollow structure), TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , and ITO. Here, the empty space in the hollow structure of the hollow silica may be filled with gas or may be a vacuum.

The size of the scatterer (335) can have a range of the following equation 1.

λ/10 < PS _QD < 5 λ Equation 1

In Equation 1, λ is the emission wavelength (nanometers) of the fluorescent substance or quantum dot, and PS _QD represents the aggregate particle size (nanometers) of the fluorescent substance or quantum dot.

As illustrated in FIGS. 1 and 3, the scatterer (335) is included in the transmission layer (340B), but as a modified example, the scatterer may also be included in the first color conversion layer (340R) and the second color conversion layer (340G).

The transmission layer (340B) may further include either a blue pigment or dye. The scattering material (335) described above may reflect external light, thereby reducing the contrast ratio, and to compensate for this problem, a blue pigment or dye may be added to the transmission layer (340B). The blue pigment or dye may absorb at least one of red light and green light included in the external light.

Referring to FIGS. 1 to 3, a second substrate (310) is positioned on the first color conversion layer (340R), the second color conversion layer (340G), and the transparent layer (340B). Although not shown, a λ/4 polarizing plate may be further included on the second substrate (310) to prevent external light reflection.

Fig. 6 is a cross-sectional view schematically showing the path of light generated in the light-emitting layer of the display device of Fig. 1.

Referring to FIG. 6, the total reflection of light is prevented by the inclined structure of the first electrode (125), and the light can be reflected by the first electrode (125) and transmitted to the color conversion layer including the first and second color conversion layers (340R, 340G) and the transmission layer (340B).

Therefore, in the display device according to one embodiment of the present disclosure, the light generated from the light-emitting layer (135) is prevented from being totally reflected between the first electrode (125) and the second electrode (145), thereby causing light loss, and the light output efficiency can be maximized by the color conversion layer and the transparent layer positioned on the light-emitting element. Since the color conversion layer according to the present embodiment is formed by including at least one fluorescent substance and one quantum dot, the color shift phenomenon that the conventional display device has can be minimized. In addition, since semiconductor nanoparticles are used as the light-emitting layer, light is emitted from the light-emitting layer in a Lambertian distribution, and accordingly, the scattering effect is greatly increased, so that the efficiency can be further increased.

FIG. 7 is a cross-sectional view showing an electrode including a rough structure in the embodiment of FIG. 1.

Referring to Fig. 7, a rough structure (115) is formed on the upper surface of the flattening layer (105) adjacent to the inclined portion (120). Due to this rough structure (115), the surface of the first electrode (125) can have a plurality of protrusions (116). The protrusions (116) can have various plane shapes such as not only a square shape but also a circle, an oval, a rhombus, a triangle, etc. Since the first electrode (125) has the protrusions (116), light generated from the light-emitting layer (135) is reflected, thereby further improving the light efficiency of the display device.

Fig. 8 is a cross-sectional view showing an embodiment in which the second electrode structure is modified from the embodiment of Fig. 1.

Referring to Fig. 8, it is mostly the same as the embodiment of Fig. 1, but there is a difference in the structure of the light-emitting layer (135). In this embodiment, the light-emitting layer (135) is connected across the light-emitting area (DA) and the non-light-emitting area (PA). The light-emitting layer (135) can be formed by full-surface deposition, and in the case of full-surface deposition, it can be coated by spin coating, slit coating, inkjet/nozzle jet printing, etc., but is not limited to these coating methods. As a result, the light-emitting layer (135) can be formed across the light-emitting area (DA) and the non-light-emitting area (PA) without being patterned, as shown in Fig. 8.

FIG. 9 is a cross-sectional view showing a display device according to one embodiment of the present disclosure. In the embodiment described in FIG. 9, the components positioned between the first substrate (50) and the second electrode (145) are substantially the same as the embodiment described in FIG. 1. However, there is a difference in the components including the color conversion layer and the transmission layer, and the parts having the difference will be described below.

Referring to Fig. 9, a first color conversion layer (540R), a second color conversion layer (540G), and a transparent layer (540B) are positioned on the second electrode (145). Most of the color conversion layer and the transparent layer (540B) are positioned within the opening (132) between the pixel defining films (130).

A blue blocking filter (522) is positioned on the first color conversion layer (540R) and the second color conversion layer (540G). A capping layer (550) is positioned on the blue blocking filter (522) and the transparent layer (540B). In FIG. 9, the blue blocking filter (522) is positioned in regions corresponding to the first color conversion layer (540R) and the second color conversion layer (540G), and the blue blocking filters (522) positioned in each region are shown as being separated from each other. However, the blue blocking filter (522) formed on the first color conversion layer (540R) and the blue blocking filter (522) formed on the second color conversion layer (540G) may be connected to each other.

Except for the differences described above, all of the contents described in FIGS. 1 to 7 can be applied as long as they do not contradict the embodiment of FIG. 9.

Fig. 10 is a cross-sectional view illustrating a display device according to one embodiment of the present disclosure. Fig. 11 is a cross-sectional view schematically illustrating a path of light generated in a light-emitting layer of the display device of Fig. 10.

The embodiment described in FIGS. 10 and 11, unlike the embodiment described in FIG. 1, exhibits a back-emitting structure, and the differences from the embodiment of FIG. 1 will be described below.

Referring to FIGS. 10 and 11, the first electrode (125) may be a semi-transparent electrode and the second electrode (145) may be a reflective electrode. In other words, the first electrode (125) may be a reflective electrode and the second electrode (145) may be a semi-transparent electrode, which is the opposite of FIG. 1, so that the second electrode (145) may reflect the light generated from the light-emitting layer (135) to send the light to the first electrode (125).

In the present embodiment, a first color conversion layer (740R), a second color conversion layer (740G), and a transparent layer (740B) including a plurality of scatterers (735) are positioned between a first substrate (50) and a light-emitting element. The light-emitting element includes a first electrode (125), a light-emitting layer (135), and a second electrode (145). Specifically, the first color conversion layer (740R), the second color conversion layer (740G), and the transparent layer (740B) may be formed within an insulating layer (110) and may be positioned between a planarization layer (105) and the first electrode (125). Light generated from the light-emitting layer (135) passes through the first electrode (125) to reach the first color conversion layer (740R), the second color conversion layer (740G), and the transmission layer (740B), and can emit red, green, and blue, respectively, while passing through them.

A blue blocking filter (722) may be positioned between the first substrate (50) and the buffer layer (55) in an area corresponding to the first color conversion layer (740R) and the second color conversion layer (740G).

In addition to the differences described above, the description of the components illustrated in Fig. 10 may be applied to the description described in Fig. 1.

Fig. 12 is a cross-sectional view showing a display device according to one embodiment of the present disclosure. Fig. 13 is a cross-sectional view schematically showing a path of light generated in a light-emitting layer of the display device of Fig. 12. The embodiment described in Fig. 12 is mostly the same as the embodiments described in Figs. 10 and 11, and differences will be described below.

Referring to FIGS. 12 and 13, the first color conversion layer (940R), the second color conversion layer (940G), and the transparent layer (940B) are positioned between the first substrate (50) and the light-emitting element. Specifically, the first color conversion layer (940R), the second color conversion layer (940G), and the transparent layer (940B) including a plurality of scatterers (935) may be formed between the first substrate (50) and the buffer layer (55), and an additional capping layer (53) may be positioned below the buffer layer (55). A light-blocking member (972) may be positioned between the first color conversion layer (940R) and the second color conversion layer (940G), between the second color conversion layer (940G) and the transparent layer (940B), and between the first color conversion layer (940R) and the transparent layer (940B). In addition, a blue blocking filter (922) may be positioned between the first color conversion layer (940R) and the first substrate (50), and between the second color conversion layer (940G) and the first substrate (50).

FIG. 14 is a cross-sectional view showing a display device according to one embodiment of the present disclosure. In the embodiment described in FIG. 14, the configurations positioned between the first substrate (50) and the planarization layer (105) with respect to the direction substantially perpendicular to the first substrate (50) are substantially the same as those in the embodiment described in FIG. 1. At this time, in the present embodiment, the only difference is that the blue blocking filter (722) is positioned between the first substrate (50) and the buffer layer (55) in the region corresponding to the first and second color filter layers (1040R, 1040G). However, since there is a difference in the configurations positioned on the insulating layer (110), the parts where there are differences will be described below.

Referring to FIG. 14, the upper surface of the insulating layer (110) may have a substantially flat structure in most areas without a slope. A light-emitting element including first and second electrodes (125, 145) and a light-emitting layer (135) is positioned on the insulating layer (110). Specifically, the first electrode (125) is positioned on the insulating layer (110), and the first electrode (125) may have a flat structure based on a plane substantially parallel to the first substrate (50). The first electrode (125) may include a transparent conductive material for back-emitting, which will be described later. For example, the first electrode (125) may include indium tin oxide, indium zinc oxide, zinc tin oxide, zinc oxide, tin oxide, gallium oxide, and the like. These may be used alone or in combination with each other.

A pixel defining film (130) is positioned on an insulating layer (110) and a first electrode (125), and an opening (132) is formed in the pixel defining film (130) to expose a portion of the first electrode (125). A side of the pixel defining film (130) formed by the opening (132) may have an inclined structure, and a light-emitting layer (135) is positioned in the opening (132). A second electrode (145) is positioned on the light-emitting layer (135), and the second electrode (145) may include a transparent conductive material.

A capping layer (150) is positioned on the second electrode (145), and a first color conversion layer (1040R), a second color conversion layer (1040G), and a transparent layer (1040B) are positioned on the capping layer (150). The display device according to the present embodiment includes a reflective metal layer (1080) on the first color conversion layer (1040R), the second color conversion layer (1040G), and the transparent layer (1040B). The reflective metal layer (1080) includes a material having reflectivity. For example, the reflective metal layer (1080) may include a metal such as aluminum, silver, platinum, gold (Au), chromium, tungsten, molybdenum, titanium, palladium (Pd), iridium (Ir), or an alloy thereof. These may be used alone or in combination with each other. In addition, the reflective metal layer (1080) may be formed as a single-layer structure or a multi-layer structure including the aforementioned metal and/or alloy. Alternatively, the reflective metal layer (1080) may have a triple-layer structure of silver (Ag)/indium tin oxide (ITO)/silver (Ag).

In this embodiment, the reflective metal layer (1080) has an inclined portion (720). The inclined portion (720) may be positioned within an opening formed between the first color conversion layer (1040R) and the second color conversion layer (1040G), between the second color conversion layer (1040G) and the transparent layer (1040B), and between the first color conversion layer (1040R) and the transparent layer (1040B). Here, the inclined portion (720) has an inclined angle (θ), and the inclined angle (θ) may be an angle greater than 0 degrees and less than 90 degrees. The reflective metal layer (1080) having the inclined portion (720) reflects the red light, green light, and blue light emitted when the light generated from the light-emitting layer (135) reaches the first color conversion layer (1040R), the second color conversion layer (1040G), and the transmission layer (1040B) and passes through them. Therefore, the efficiency of the light finally emitted in the direction from the second substrate (1010) described below toward the first substrate (50) can be further improved.

A second substrate (1010) is positioned on the reflective metal layer (1080).

Except for the differences described above, all of the contents described in FIGS. 1 to 7 can be applied as long as they do not contradict the embodiment of FIG. 14.

FIG. 15 is a cross-sectional view showing a reflective metal layer including a rough structure in the embodiment of FIG. 14.

Referring to Fig. 15, a plurality of protrusions (716) are formed on a reflective metal layer (1080) having an inclined portion (720). In order to form a plurality of protrusions (716), an auxiliary layer (790) having a rough structure (715) may be further included between the second substrate (1010) and the reflective metal layer (1080). The auxiliary layer (790) may be an organic material.

Since the reflective metal layer (1080) has a plurality of protrusions (716), light emitted from the first color conversion layer (1040R), the second color conversion layer (1040G), and the transparent layer (1040B) is reflected, thereby further improving the light efficiency of the display device.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

125: 1st electrode 145: 2nd electrode
116, 716: Protrusion 372, 972: No shading
120, 720: Slope 115, 715: Rough Structure
335, 735, 935: Scatterer 340R, 540R, 740R, 1040R: 1st color conversion layer
340G, 540G, 740G, 1040G: Second color conversion layer
340B, 540B, 740B, 1040B: Transmittance layer
135: Emitting layer 322, 522, 722, 922: Blue blocking filter

Claims (20)

1st substrate,
A transistor positioned on the first substrate,
An insulating layer positioned above the transistor and having an opening and a slope,
A first electrode positioned on the above insulating layer,
A light-emitting layer positioned on the first electrode,
A second electrode positioned on the above light-emitting layer,
A plurality of color conversion layers positioned on the second electrode, and
Including an optical filter layer positioned between the second electrode and the plurality of color conversion layers,
The first electrode includes a portion inclined along the slope of the insulating layer with respect to a plane parallel to the first substrate,
The above light-emitting layer contains semiconductor nanoparticles,
The above first electrode
A first flat portion located in the above opening,
the inclined portion positioned along the above slope, and
Including a second flat portion connected to the above inclined portion,
A display device in which the first electrode is electrically connected to the transistor by penetrating the insulating layer in the second flat portion. In paragraph 1,
Further comprising a pixel defining film positioned on the insulating layer,
A display device in which the pixel definition film overlaps the side surface of the inclined portion. In paragraph 2,
Further comprising a planarizing layer positioned between the first substrate and the insulating layer,
A display device in which the inclined portion of the first electrode positioned on the inclined portion of the insulating layer is extended so that the second electrode is positioned on the flattening layer. In paragraph 3,
A display device in which the pixel defining film includes dispersed nano-structured scattering particles. In paragraph 1,
A display device having an inclination angle greater than 0 and less than 90 degrees. In paragraph 1,
A display device wherein the first electrode includes a reflective electrode. In Article 6,
A display device wherein the first electrode includes a plurality of protrusions. In paragraph 1,
A display device wherein the above-mentioned light-emitting layer includes quantum dots that emit blue light. In Article 8,
A display device wherein the plurality of color conversion layers include a first color conversion layer and a second color conversion layer, and the display device further includes a transparent layer adjacent to at least one of the first color conversion layer and the second color conversion layer in a direction parallel to the upper surface of the first substrate, and the transparent layer includes a plurality of scattering bodies. In paragraph 1,
A display device further comprising a capping layer positioned between the second electrode and the color conversion layer. In paragraph 1,
Further comprising a pixel defining film positioned on the insulating layer and having an opening,
A display device in which the plurality of color conversion layers are positioned within the opening. In paragraph 1,
A display device in which the above-mentioned light-emitting layer forms a tandem structure including quantum dots that emit blue light. In paragraph 1,
A display device wherein the first substrate includes a first light-emitting region, a second light-emitting region, and a non-light-emitting region positioned between the first light-emitting region and the second light-emitting region, and the light-emitting layer is connected across the first light-emitting region, the non-light-emitting region, and the second light-emitting region. 1st substrate,
An insulating layer positioned on the first substrate,
A light-emitting element positioned on the insulating layer and including a light-emitting layer,
A plurality of color conversion layers positioned on the light-emitting element, and
Including a reflective metal layer positioned on the plurality of color conversion layers,
The above light-emitting layer contains semiconductor nanoparticles,
The above reflective metal layer includes a sloped portion,
A display device in which the inclined portion of the reflective metal layer is located within an opening formed between the first color conversion layer and the second color conversion layer, which are adjacent to each other among the plurality of color conversion layers.
delete delete In Article 14,
Further comprising a blue blocking filter overlapping the first color conversion layer and the second color conversion layer,
A display device in which the above blue blocking filter is positioned between the first substrate and the insulating layer. delete delete delete

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